Two rail overhead conveyor device

ABSTRACT

A two rail overhead conveyor device for meat processing is disclosed comprising an eviscerating platform conveyor, an entrance or feed rail, a lower rail for smaller carcasses and an upper rail for larger carcasses running parallel to each other above the eviscerating platform, a sensor to detect carcass size, a first rail switch connected to the sensor to direct the carcasses to either the upper or lower rail, an incline conveyor to raise the larger carcasses to the upper rail level, an indexing switch to regulate the flow of carcasses to the eviscerating area, a conveyor chain to propel the carcasses along the rails, and a second rail switch and detector to coordinate the transfer of eviscerated carcasses from the upper and lower rails to the exit rail. The conveyor chain comprises combination chain links having a drop finger and a spring loaded side finger with the side finger engaging and propelling the carcass trolley frames riding on the upper rail while the drop fingers engage and propel the trolley frames riding on the lower rails. 
     An alternate embodiment utilizes a gravity rail drive rather than a conveyor chain to propel the carcasses to and from the eviscerating area with a conveyor chain functioning only to synchronize the movement of the carcasses over the eviscerating area with the eviscerating platform conveyor.

This is a division of application Ser. No. 869,006 filed Jan. 12, 1978.

BACKGROUND OF THE INVENTION

This invention relales to a conveyor and more particularly to a two railoverhead conveyor device for meat processing. In meat processing plants,the animal will be conveyed while hanging from a conveyor over aneviscerating conveyor upon which a person riding moves at the same speedas the animal on the overhead conveyor. As the animal moves along withthe eviscerating conveyor, the workmen will remove the internal organsof the animal. Prior conveyors have only one rail and one power chainfor moving the animals over the eviscerator conveyor. If the animals areof different sizes, difficulty is encountered by the workmen in reachingthe particular areas of the animals, and different viscera tables mayhave to be established with separate rails and conveyor chains toaccommodate the different sizes. This is both unduly time consuming andinefficient.

SUMMARY OF THE INVENTION

A two rail overhead conveyor device for meat processing is disclosedcomprising an eviscerating platform conveyor an entrance or feed rail, alower rail for smaller carcasses and an upper rail for larger carcassesrunning parallel to each other above the eviscerating platform, a sensorto detect carcass size, a first rail switch connected to the sensor todirect the carcasses to either the upper or lower rail, an inclineconveyor to raise the larger carcasses to the upper rail level, anindexing switch to regulate the flow of carcasses to the evisceratingarea, a conveyor chain to propel the carcases along the rails, and asecond rail switch and detector to coordinate the transfer ofeviscerated carcasses from the upper and lower rails to the exit rail.The conveyor chain comprises combination chain links having a dropfinger and a spring loaded side finger with the side finger engaging andpropelling the carcass trolley frames riding on the upper rail while thedrop fingers engage and propel the trolley frames riding on the lowerrails.

An alternate embodiment utilizes a gravity rail drive rather than aconveyor chain to propel the carcasses to and from the eviscerating areawith a conveyor chain functioning only to synchronize the movement ofthe carcasses over the eviscerating area with the eviscerating platformconveyor.

It is a principal object of this invention to provide an improvedoverhead conveyor device for meat processing.

A further object of the invention is to provide a two rail overheadconveyor device for meat processing wherein both large and small animalcarcasses are transported across an eviscerating platform conveyor at auniform height.

A still further object of the invention is to provide a two railoverhead conveyor device for meat processing that automatically deliverslarge carcasses to the upper transporting rail and smaller carcasses tothe lower transporting rail for uniform height above an evisceratingarea.

A still further object of the invention is to provide a two railoverhead conveyor device for meat processing that utilizes only oneconveyor chain to transport both large and small animal carcasses at auniform height above an eviscerating area.

A still further object of the invention is to provide a two railoverhead conveyor device for meat processing that utilizes gravity totransport carcasses to and from an eviscerating area and maintains bothlarge and small carcasses at a uniform height above an evisceratingarea.

A still further object of the invention is to provide a two railoverhead conveyor device for meat processing that utilizes a conveyorchain comprised of chain links having both a side finger and drop fingerassembly.

A still further object of the invention is to provide a two railoverhead conveyor device for meat processing that utilizes a conveyorchain comprised of chain links having both a drop finger and a springloaded side finger.

A still further object of the invention is to provide a two railoverhead conveyor device for meat processing that automatically deliversboth large and small animal carcasses to an eviscerating area at auniform height above the eviscerating area.

A still further object of the invention is to provide a two railoverhead conveyor device for meat processing that is economical tomanufacture, durable in use and automatic in operation.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention consists in the construction, arrangements andcombination of the various parts of the device whereby the objectscontemplated are attained as hereinafter more fully set forth,specifically pointed out in the claims, and illustrated in theaccompanying drawings in which:

FIG. 1 is a top plan view of the device.

FIG. 2 is an enlarged front view seen on line 2--2 of FIG. 1.

FIG. 3 is an enlarged front view seen on line 3--13 of FIG. 1.

FIG. 4 is an enlarged elevation view seen on line 4--4 of FIG. 1.

FIG. 5 is a view similar to FIG. 4 with the trolley frames riding thelower track.

FIG. 6 is an enlarged side view of a combination chain link.

FIG. 7 is a bottom view seen on line 7--7 of FIG. 6.

FIG. 7A is a view similar to FIG. 7 showing an alternate embodiment.

FIG. 8 is an enlarged side view of a chain link having a drop finger.

FIG. 9 is a bottom view seen on line 9--9 of FIG. 8.

FIG. 10 is an enlarged side view of a chain link having a side finger.

FIG. 11 is a bottom view seen on line 11--11 of FIG. 10.

FIG. 12 is a top schematic view of a conveyor chain.

FIG. 13 is a side view seen on line 13--13 of FIG. 12.

FIG. 14 is a front elevation view of a carcass being propelled by thechain of FIG. 12.

FIG. 15 is an enlarged sectional view seen on line 15--15 of FIG. 14.

FIG. 16 is another front elevation view of a carcass being propelled bythe chains of FIG. 12.

FIG. 17 is an enlarged sectional view seen on line 17--17 of FIG. 16.

FIG. 18 is an enlarged sectional view of two carcasses passing over theeviscerating area.

FIG. 19 is a top plan view of an alternate embodiment of FIG. 1.

FIG. 20 is an enlarged side view seen on line 20--20 of FIG. 19.

FIG. 21 is an alternate embodiment of a combination link.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The numeral 10 generally refers to the two rail overhead conveyor deviceshown in FIG. 1.

Conveyor device 10 is comprised of entrance rail section 12, lower rail14, upper rail 16, and exit rail section 18. Lower rail 14 and upperrail 16 are substantially parallel as they pass above evisceratingplatform conveyor 20 with rail 14 being below rail 16. Entrance railsection 12, lower rail 14 and exit rail section 18 are all atapproximately the same level. Conveyor delivery rail section 22 connectsentrance rail section 12 to inclined conveyor 24 and exhibits a gravitydrop therebetween. Incline rail section 26 is connected at one end torail section 22 and runs along incline conveyor 24 for connection toupper feed rail section 28 as shown in FIG. 1. Upper rail 16 isconnected at one end to rail section 28, transverses the evisceratingarea 30 above platform conveyor 20 and is connected to exit deliveryrail section 32. Rail section 32 exhibits a gravity drop from upper rail16 to its operational attachment to exit rail section 18. Lower rail 14on the other hand is in direct linear alignment with and attached toentrance rail section 12 at one end and exit rail section 18 at theother end as shown in FIG. 1.

Trolley frame 34 (FIGS. 15 and 17) is adapted to carry an animal carcassand ride on the above mentioned rails. Trolley frame 34 comprisestrolley wheel 36 rotatably mounted to downwardly extending supportmember 38. Eyelet 40 is securely attached to the lower portion 42 ofsupport member 38 and flexibly supports a meat hook 14. Theaforementioned rails matingly receive trolley wheel 36 such that trolleyframe 34 may be propelled along any of the aforementioned rail sections.

Trolley frames 34 are propelled along the rails by an endless conveyorchain assembly 46 comprising a conveyor chain 48, chain guide 50 (FIG.17), chain sprockets 52 and means (not shown) to move conveyor chain 48along chain guide 50 at a constant linear speed. Chain guide 50 islocated directly above entrance rail 12, lower rail 14, and exit railsection 18 in a single continuous run.

Conveyor chain 48 is comprised of a plurality of interconnecting linksof either combination links 54 (FIG. 6), and/or drop finger links 56(FIG. 8), and/or side finger links 58 (FIG. 10). Combination link 54 hasa downwardly extending drop finger 60 and a transversely extendingspring loaded side finger 62 while link 56 has a downwardly extendingdrop finger 64 and link 58 has a transversely extending spring loadedside finger 66. Side finger 62 is yieldably maintained against stop 68by biasing spring 70 and is pivotable away from stop 68 by a forceovercoming biasing spring 70 as illustrated by the phantom line in FIG.7. Link 54" is an alternate embodiment of link 54 with side finger 62"pivoting in a direction opposite to side finger 62 as illustrated by thephantom lines in FIG. 7A. Link 65 of FIG. 21 is another alternateembodiment having an offset side finger 67.

A plurality of the above described links are interconnected end to endto form a continuous conveyor chain and may be comprised of one or allof the above described links. Conveyor chain 48 (FIGS. 4 and 5) iscomprised of combination links 54 appropriately spaced while conveyorchain 48" (FIGS. 12, 13, 14 and 16) is comprised of alternating pairs oflinks 56 and 58. The drop fingers and/or side fingers of the links maymake contact with and propel the trolley frames 34 along the rails. Railguide 50 is directly above entrance rail section 12, lower rail 14 andexit rail section 18 such that a trolley frame riding any one of theserail sections will be in contact with a drop finger and propelledthereby along the rail section. FIG. 5 shows a trolley frame 34 beingpropelled by drop finger 60 of combination link 54 while FIG. 16 shows atrolley frame 34 being propelled by drop finger 64 of drop finger 56.The side fingers are utilized to propel a trolley frame 34 along upperrail section 16. Upper rail 16 is in close proximity and parallel tochain guide 50 such that the side finger will make contact with supportmember 38 of a trolley frame 34 riding on upper rail 16 as shown in FIG.15. FIGS. 4 and 15 show a trolley frame 34 on upper rail 16 beingpropelled by side finger 62 of combination link 54 while FIG. 14 shows atrolley frame 34 in contact with and propelled by side finger 66 of link58. The use of both drop fingers and side fingers on the same conveyorchain allows one conveyor chain to propel trolley frames along twodistinct rail runs at different heights. In conveyor device 10, conveyorchain 48 provides the propulsion force for the trolley frames 34 withcarcasses for entrance rail section 12, lower rail 14, upper rail 16,and exit rail section 18 while the force of gravity and inclinedconveyor 24 provide the propulsion force as will be hereinafter moreparticularly described for conveyor delivery rail section 22, inclinerail section 26, upper feed rail section 28, and exit delivery railsection 32 (FIG. 1).

Light sensor 72 and light 74 are located in linear alignment on oppositesides of entrance rail section 12 with light sensor 72 electricallyconnected to electric rail switch 76 for detection and differentiationof animal carcasses according to size. It is desired that the longercarcasses travel over eviscerating platform conveyor 20 on the upperrail section, and that the shorter carcasses travel over the conveyor 20on the lower rail 14 so that the area of both the shorter and longercarcasses to be eviscerated is at substantially the same height aboveplatform conveyor 20. The relative positioning of a short carcass 80riding on lower rail 14 and a long carcass 78 riding on upper rail 16 toplatform conveyor 20 is shown in FIG. 18. As the carcasses aretransported along entrance rail section 12 toward the eviscerating area,a longer carcass 78 will break the beam of light between light 74 andlight sensor 72 while a shorter carcass 80 will pass above the lightbeam leaving it undisturbed as illustrated in FIG. 2. Rail switch 76 islocated at the junction of entrance rail section 12, lower rail 14, andconveyor delivery rail section 22 and functions to direct an incomingtrolley frame 34 from rail section 12 to either lower rail 14, orconveyor delivery rail 22. Detection of a longer carcass 78 by sensor 72activates rail switch 76 to divert longer carcass 78 onto conveyordelivery rail section 22 for ultimate delivery to upper rail 16. Ashorter carcass 80 will not interrupt the beam of light from light 74and therefore will pass light sensor 72 undetected and will continuestraight through from entrance rail section 12 to lower rail 14 as railswitch 76 will not be activated. Rail switch 76 must be activated todivert trolley frames from entrance rail section 12 to conveyor deliverysection 22. Once the longer carcass 78 is diverted by rail switch 76 toconveyor delivery rail section 22, it encounters limit switch 82 whichdeactivates rail switch 76. Limit switch 82 is located approximatelymidway on conveyor delivery rail section 22. Light sensor 72 inconjunction with rail switch 76 and limit switch 82 provides automaticdetection and separation of larger carcasses 78 and smaller carcasses80.

Conveyor delivery section 22, incline rail section 26, incline conveyor24 and upper feed rail section 28 function to raise the larger carcassesfrom the lower level of entrance rail section 12 to the higher level ofupper rail 6. Conveyor delivery rail section 22 branches away fromconveyor chain assembly 46 such that the drop fingers no longer propelthe trolley frames 34. A gravity drop is utilized to propel thecarcasses along section 22 from the junction with rail section 12 to theincline conveyor area. A five inch gravity drop along rail section 22 ispreferred (FIG. 3). Upon reaching the conveyor area at the terminationof conveyor delivery rail section 22, trolley frame 34 is engaged byconveyor finger 84 of incline conveyor 24. Conveyor finger 84 propelsthe trolley frame 34 along incline rail section 26 to upper feed railsection 28. Upper feed rail section 28 also exhibits a gravity drop topropel the trolley frame 34 and carcass to upper rail 16. Indexer 86 islocated on rail section 28 and is electrically connected to limit switch88 to coordinate the flow of carcasses to the eviscerating area. Sinceit is desirable to maintain a preselect distance between carcassespassing over the eviscerating area, preferably six feet, indexer 86delays the longer carcasses from entering the in feeding area 90 forupper rail 16 when a shorter carcass is entering the in feeding area forlower rail 14 as detected by limit switch 88. In other words, a shortercarcass on lower rail 14 will activate limit switch 88 to in turnactivate indexer 86 to delay any introduction of longer carcasses to theeviscerating area. Since the shorter carcasses are being propelled atthis point by conveyor chain assembly 46 while the longer carcasses aresubject to propulsion by the gravity drop of section 28, it isadvantageous to delay the entrance of the longer carcasses rather thanthe shorter ones.

The linear velocity of conveyor chain 48 is identical to the linearvelocity of platfrom conveyor 20 so that a workman standing on conveyorplatform 20 may eviscerate the carcass as it travels along above theconveyor platform. As previously noted, the longer carcasses 78 andshorter carcasses 80 are approximately the same height above platformconveyor 20 because of the relative height differences above theplatform of lower rail 14 and upper rail 16 as shown in FIG. 12. Thus,the eviscerating workmen may operate more efficiently and convenientlyhaving all carcasses at approximately the same relative height.

A shorter carcass is propelled by a drop finger over the evisceratingarea, while the larger carcasses are propelled by a side finger. Oncethe longer carcasses are eviscerated and reach the termination of upperrail 16, exit delivery rail section 32 veers away from chain assembly 46to disengage the side finger from trolley frame 34. Since the largercarcass 78 is no longer being propelled by conveyor chain 48, exitdelivery rail section 32 exhibits gravity drop of preferably 5 inches todeliver the carcass from the end of upper rail 16 to exit rail section18. The end of exit delivery rail section 32 is detachably connected toexit rail section 18 such that the trolley frame 34 carrying the largercarcass automatically runs off rail 32 onto rail 18 at the junctionthereof. For a smaller carcass to be transferred from lower rail 14 torail 18, rail 32 is automatically disengaged by rail control switch 92.As the small carcass approaches exit rail section 18, it activates limitswitch 94. Limit switch 94 is electrically connected to rail controlswitch 92 such that the activation of limit switch 94 by the smallcarcass in turn activates rail control switch 92 to disconnect rail 32and allow the smaller carcass to pass from lower rail 14 to exit railsection 18. Rail section 32 automatically reconnects to rail section 18after the smaller carcass has exited. The carcasses are so spaced apartwhen passing over the eviscerating area 30 that there is no possibilitythat a larger carcass and a smaller carcass will approach the junctionof rail 32 to 14 and 18 contemporaneously. Both the larger carcasses andthe smaller carcasses are propelled along exit rail section 18 by thedrop finger.

In operation, a carcass attached to trolley frame 34 is transportedtoward the eviscerating area on entrance rail section 12 by a dropfinger 60 of conveyor chain 48 being in contact with the trolley frame.Light sensor 72 detects whether the carcass is the shorter carcass or alonger carcass. If a shorter carcass continues to be propelled by dropfinger 60 and travels from entrance rail section 12 onto lower rail 14,and continues over conveyor platform 20 for evisceration. Conveyor chain48 is moving at the same speed as platform conveyor 20 such that aworkman standing on platform 20 opposite the carcass can eviscerate thecarcass as the carcass continues down the rail. As the small carcassexits the eviscerating area 30, it activates limit switch 94 which inturn activates rail control switch 92 to allow the trolley frame to ridefrom lower rail 14 to exit rail section 18 and away from theeviscerating area.

A larger carcass proceeding along entrance rail section 12 will activatelight sensor 72 thereby activating electric rail switch 76 to divert thelarger carcass from rail 12 to conveyor delivery rail section 22. Thegravity drop of rail 22 will deliver the larger carcass, the trolleyframe of which has become disengaged from the drop finger of conveyorchain 48 because of the veering away of rail 22 from chain 48, to theinclined conveyor 24. A finger 84 of inclined conveyor 24 will thenengage trolley frame 34 to propel it along incline rail section 26thereby raising the longer carcass well above lower rail 14. At the endof incline rail section 26, incline conveyor 24 disengages from trolleyframe 34 at the beginning of another gravity drop on upper feed railsection 28. This gravity drop will propel the larger carcass trolleyframe along upper feed rail section 28 to the in feeding area 90 forupper rail 16. At this point, a side finger 62 of conveyor chain 48 willengage trolley frame 34 to propel it along upper rail 16 thus conveyingthe larger carcass across the eviscerating area 30. Since the largercarcass is being propelled by the conveyor chain as was the smallercarcass, it is also moving at the same rate across the eviscerating area30 as the platform conveyor 20 (FIG. 18). As the larger carcass exitsthe eviscerating area from upper rail 16 to exit delivery rail section32, side finger 62 disengages from trolley frame 34 as section 32 swingsaway from conveyor chain 48. A gravity drop on section 32 propels thelarger carcass from the end of upper rail 16 to lower rail 18 as thechain is disengaged from the trolley frame. At this point, section 32 iscontiguous with exit rail section 18 such that the trolley frame rollsdirectly onto rail 18 from rail 32 and the longer carcass exits alongrail 18 propelled by a drop finger 60 from conveyor chain 40. Thus, thecarcasses are automatically separated and delivered to the evisceratingarea at the proper height, and automatically removed therefrom by thistwo rail-single conveyor chain device.

An alternate embodiment of conveyor device 10 is shown in FIG. 19, andis generally referred to by the numeral 10'. Conveyor device 10' is agravity fed device with a conveyor chain 48' utilized only tosynchronize the linear velocity of the carcasses as they pass over theeviscerating area 30 to the linear velocity of the platform conveyor 20.

Similar to conveyor device 10 conveyor device 10' comprises entrancerail section 12', lower rail 14', exit rail section 18', upper feed railsection 28', upper rail 16' and exit delivery rail section 32'. Entrancerail section 12' is at a greater height than exit rail section 18' sothat the force of gravity is used to propel the carcasses along much ofthe above mentioned rail sections. Entrance rail section 12' iscontiguous to lower rail 14' which in turn is contiguous to exit railsecton 18'. A gravity drop exists between rail section 12' and lowerrail 14'.Upper feed rail section 28' is detachably connected to entrancerail section 12'. At the junction of rail 12' and lower rail 14' upperfeed rail section 28' also exhibits a gravity drop to propel the carcassto the feeding area 90' for upper rail 16'. Sensor 72' and associatedlight 74' detect the longer carcasses and activate rail switch 76' todirect the longer carcasses from rail 12' to rail 28'. Rail switch 76'is deactivated by limit switch 82' as the larger carcass enters feedingarea 90'.

Conveyor chain 48' is utilized to synchronize the speed of both theshorter and longer carcasses in their travel over the eviscerating area30 to the speed of platform conveyor 20. Conveyor chain 48' is comprisedof combination links 54 such that drop finger 60 engages the hanger 34of the smaller carcass and side finger 62 engages the hanger of a largercarcass as they enter the end feeding area 90'. Conveyor chain 48' isarranged in an endless configuration around sprockets 52' roller turns52", with horizontal drive motor 96 driving the chain. The propertension in chain 48' is maintained by weight 98 attached to one of thesprockets 52' in a conventional manner.

As a smaller carcass leaves the eviscerating area, the hanger 34disengages from drop finger 60 and the carcass continues to move by theforce of gravity from lower rail 14' onto exit rail section 18' and awayfrom the eviscerating area. The hanger 34 of a longer carcass riding onupper rail 16' disengages from side finger 62 as it leaves theeviscerating area and is propelled along exit delivery rail section 32'by a gravity drop in section 32'. A limit switch 94' located on section32' is activated by the longer carcass to connect via rail switch 92',section 32' to exit rail section 18'. The larger carcass thus travelsalong rail section 32' to exit rail section 18' and away from theeviscerating area. Rail switch 92' automatically deactivates anddetaches rail section 32' from 18' after the larger carcass passes.

In operation, the carcasses travel along entrance rail section 12' bygravity and the rate of admissions is controlled by indexer 100 locatedjust before sensor 72'. A smaller carcass passes through sensor 72'undetected and continues on to lower rail 14'. The drop finger 60 of alink in conveyor chain 48' engages the trolley frame 34 of the shortercarcass and the carcass is propelled over rail 14' at a speed identicalto that of platform conveyor 20. The carcass is eviscerated and thetrolley frame 34 disengages from drop finger 60 as the carcass leavesthe eviscerating area. The carcass continues along by force of gravityand exits via exit rail section 18'. A larger carcass entering alongentrance rail section 12' is detected by sensor 72' that in turnactivates rail switch 76'. Rail switch 76' connects upper feed railsection 28' to rail 12' such that the larger carcass is directed ontoupper feed rail section 28' and is propelled by gravity into the endfeeding area 90'. The larger carcass activates limit switch 82' todisengage rail 28' from rail 12'. The side finger 62 engages the trolleyframe of the larger carcass and transports it across the evisceratingarea. Upon leaving the eviscerating area, the side finger 62 isdisengaged from the trolley frame 34 and the eviscerated larger carcassis propelled by a gravity drop along exit delivery rail section 32'. Thelarger carcass activates the limit switch 94' which in turn activatesrail switch 92' to connect section 32' to exit rail section 18'. Thelarger carcass travels down rail 32' onto exit rail 18' and away fromthe eviscerating area. Rail switch 92' is then automatically deactivatedto disconnect rail section 32' from rail section 18'.

Thus, it can be seen that this device accomplishes at least all of itsstated objectives.

What is claimed is:
 1. In combination,a revolving eviscerating platform conveyor apparatus adpated to support a workman, said platform adapted to revolve at a constant speed, and a two rail overhead conveyor device for meat processing comprising, a first rail means adapted to guide and support a conveyor trolley frame having a carcass attached thereto, said first rail means having a first end portion, a middle portion transversing over said platform conveyor at a first predetermined height therefrom and a second end portion, a second rail means adapted to guide and support a conveyor trolley frame having a carcass attached thereto, said second rail means having a first end portion, a middle portion transversing over said platform conveyor at a second predetermined height therefrom and a second end portion, first connection means for selectively detachably connecting said first end portion of said second rail means to said first rail means at a point before said middle portion, first means for propelling a conveyor trolley frame having a carcass attached thereto at said constant speed along said middle portion of said first rail means and along said middle portion of said second rail means, second means for propelling a conveyor trolley frame having a carcass attached thereto along said first end portion and said second end portion of said first rail means, third means for propelling a conveyor trolley frame having a carcass attached thereto along said first end portion and said second end portion of said second rail means, and a detection means operationally attached to said first end portion of said first rail means to detect a carcass of a predetermined size, attached to a conveyor trolley frame on said first end portion, said detection means being connected to said first connection means so that the detection of a carcass of said predetermined size activates said first connection means thereby guiding said trolley frame and carcass attached thereto onto said first end portion of said second rail means from said first end portion of said first rail means.
 2. The combination of claim 1 wherein said first means for propelling said conveyor trolley frame comprises,a first conveyor chain guide adapted to receive a conveyor chain, said first guide being parallel to and above said middle portion of said first rail means, a conveyor chain having a plurality of interconnected links within said guide, means attached to said chain for engaging and propelling said trolley frames, and first power means for driving said chain at said constant speed.
 3. The combination of claim 2 wherein said means for engaging and propelling said trolley frame comprises a first transversely extending side finger member attached to some of said links of said chain adapted for engagement of said trolley frames on said middle portion of said second rail means, and a first downwardly disposed drop finger member attached to the others of said links of chain adapted for engagement of said trolley frames on said middle portion of said first rail means.
 4. The combination of claim 3 wherein said first side finger members are pivotally attached to said respective links and have a spring bias means attached thereto to yieldably maintain a transverse disposition to said links.
 5. The combination of claim 2 wherein said means for engaging and propelling said trolley frame comprises said conveyor chain links with each said link having a combination second transversely extending side finger member and second downwardly disposed drop finger member attached thereto, said second side finger member adapted to engage and propel said trolley frames on said middle portion of said second rail means and said second drop finger member adapted to engage and propel said trolley frames on said middle portion of said first rail means.
 6. The combination of claim 5 wherein said second side finger member is pivotally attached to each said link and is yieldably maintained in a transverse disposition by a spring bias means.
 7. The combination of claim 2 wherein said second means for propelling said conveyor trolley frame comprises said first conveyor chain guide and said chain extending along and parallel to said first end portion and said second end portion of said first rail means.
 8. The combination of claim 7 wherein said third means for propelling said conveyor trolley frame comprises said first end portion of said second rail means, havinga first gravity drop rail portion, one end of said first gravity drop portion selectively, detachably connected to said first end portion of said first rail means, an incline conveyor means located at the other end of said first gravity drop portion such that the force of gravity propels a trolley frame along said first gravity drop portion to said incline conveyor means, said incline conveyor means adapted to propel said trolley frame to a height above said middle portion of said second rail means, a second gravity drop rail portion operationally connected at one end to said incline conveyor means and at the other end to said middle portion of said second rail means so that the force of gravity will propel a trolley frame from said incline conveyor means to said middle portion, and said second end portion of said second rail means having a third gravity drop rail portion, said second end portion attached at one end to said middle portion and at the other end selectively, detachably secured to said second end portion of said first rail means so that a trolley frame is propelled by gravity from said middle portion of said second rail means to said second end portion of said first rail means.
 9. The combination of claim 2 wherein said second means for propelling said conveyor trolley frame comprises said first end portion of said first rail means being inclined toward said middle portion of said first rail means so that the force of gravity propels said trolley frame along said first end portion to said middle portion and said second end portion being inclined away from said middle portion so that the force of gravity propels said trolley frame along said second end portion away from said middle portion.
 10. The combination of claim 9 whereby said third means for propelling said conveyor trolley frame comprises said first end portion of said second rail means being inclined toward said middle portion of said second rail means so that the force of gravity propels said conveyor trolley frame along said first end portion of said second rail means to said middle portion of said second rail means and said second end portion of said second rail means being inclined away from said middle portion so that the force of gravity propels said trolley frames from said middle portion along said second end portion of said second rail means to said second end portion of said first rail means.
 11. The combination of claim 1 wherein said second end portion of said second rail means has a second connection means for selectively, detachably connecting said second end portion of said second rail means to said second end portion of said first rail means. 